Package it.unimi.dsi.fastutil.ints

Class IntOpenHashBigSet

java.lang.Object
java.util.AbstractCollection<java.lang.Integer>
it.unimi.dsi.fastutil.ints.AbstractIntCollection
it.unimi.dsi.fastutil.ints.AbstractIntSet
it.unimi.dsi.fastutil.ints.IntOpenHashBigSet
All Implemented Interfaces:
Hash, IntCollection, IntIterable, IntSet, Size64, java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<java.lang.Integer>, java.util.Collection<java.lang.Integer>, java.util.Set<java.lang.Integer>
public class IntOpenHashBigSet
extends AbstractIntSet
implements java.io.Serializable, java.lang.Cloneable, Hash, Size64
A type-specific hash big set with with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a big set: the number of elements in the set is limited only by the amount of core memory. The table (backed by a big array) is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create sets with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.

Note that clear() does not modify the hash table size. Rather, a family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

The methods of this class are about 30% slower than those of the corresponding non-big set.

See Also:
Hash, HashCommon, Serialized Form

  • Constructor Details

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(long expected, float f)
      Creates a new hash big set.

      The actual table size will be the least power of two greater than expected/f.

      Parameters:
      expected - the expected number of elements in the set.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(long expected)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor.
      Parameters:
      expected - the expected number of elements in the hash big set.

    • IntOpenHashBigSet

      public IntOpenHashBigSet()
      Creates a new hash big set with initial expected Hash.DEFAULT_INITIAL_SIZE elements and Hash.DEFAULT_LOAD_FACTOR as load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(java.util.Collection<? extends java.lang.Integer> c, float f)
      Creates a new hash big set copying a given collection.
      Parameters:
      c - a Collection to be copied into the new hash big set.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(java.util.Collection<? extends java.lang.Integer> c)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given collection.
      Parameters:
      c - a Collection to be copied into the new hash big set.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(IntCollection c, float f)
      Creates a new hash big set copying a given type-specific collection.
      Parameters:
      c - a type-specific collection to be copied into the new hash big set.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(IntCollection c)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific collection.
      Parameters:
      c - a type-specific collection to be copied into the new hash big set.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(IntIterator i, float f)
      Creates a new hash big set using elements provided by a type-specific iterator.
      Parameters:
      i - a type-specific iterator whose elements will fill the new hash big set.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(IntIterator i)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by a type-specific iterator.
      Parameters:
      i - a type-specific iterator whose elements will fill the new hash big set.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(java.util.Iterator<?> i, float f)
      Creates a new hash big set using elements provided by an iterator.
      Parameters:
      i - an iterator whose elements will fill the new hash big set.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(java.util.Iterator<?> i)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor using elements provided by an iterator.
      Parameters:
      i - an iterator whose elements will fill the new hash big set.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(int[] a, int offset, int length, float f)
      Creates a new hash big set and fills it with the elements of a given array.
      Parameters:
      a - an array whose elements will be used to fill the new hash big set.
      offset - the first element to use.
      length - the number of elements to use.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(int[] a, int offset, int length)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor and fills it with the elements of a given array.
      Parameters:
      a - an array whose elements will be used to fill the new hash big set.
      offset - the first element to use.
      length - the number of elements to use.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(int[] a, float f)
      Creates a new hash big set copying the elements of an array.
      Parameters:
      a - an array to be copied into the new hash big set.
      f - the load factor.

    • IntOpenHashBigSet

      public IntOpenHashBigSet​(int[] a)
      Creates a new hash big set with Hash.DEFAULT_LOAD_FACTOR as load factor copying the elements of an array.
      Parameters:
      a - an array to be copied into the new hash big set.

  • Method Details

    • toBigSet

      public static IntOpenHashBigSet toBigSet​(java.util.stream.IntStream stream)
      Collects the result of a primitive Stream into a new big hash set.

      This method performs a terminal operation on the given Stream

      API Notes:
      Taking a primitive stream instead of returning something like a Collector is necessary because there is no primitive Collector equivalent in the Java API.

    • toBigSetWithExpectedSize

      public static IntOpenHashBigSet toBigSetWithExpectedSize​(java.util.stream.IntStream stream, long expectedSize)
      Collects the result of a primitive Stream into a new big hash set.

      This method performs a terminal operation on the given Stream

      API Notes:
      Taking a primitive stream instead returning something like a Collector is necessary because there is no primitive Collector equivalent in the Java API.

    • addAll

      public boolean addAll​(java.util.Collection<? extends java.lang.Integer> c)
      Description copied from class: AbstractIntCollection
      Specified by:
      addAll in interface java.util.Collection<java.lang.Integer>
      Specified by:
      addAll in interface java.util.Set<java.lang.Integer>
      Overrides:
      addAll in class AbstractIntCollection

    • addAll

      public boolean addAll​(IntCollection c)
      Description copied from interface: IntCollection
      Adds all elements of the given type-specific collection to this collection.
      Specified by:
      addAll in interface IntCollection
      Overrides:
      addAll in class AbstractIntCollection
      Parameters:
      c - a type-specific collection.
      Returns:
      true if this collection changed as a result of the call.
      See Also:
      Collection.addAll(Collection)

    • add

      public boolean add​(int k)
      Description copied from class: AbstractIntCollection
      Ensures that this collection contains the specified element (optional operation).
      Specified by:
      add in interface IntCollection
      Overrides:
      add in class AbstractIntCollection
      See Also:
      Collection.add(Object)

    • remove

      public boolean remove​(int k)
      Description copied from class: AbstractIntSet
      Removes an element from this set. Delegates to the type-specific rem() method implemented by type-specific abstract Collection superclass.
      Specified by:
      remove in interface IntSet
      Overrides:
      remove in class AbstractIntSet
      See Also:
      Collection.remove(Object)

    • contains

      public boolean contains​(int k)
      Description copied from class: AbstractIntCollection
      Returns true if this collection contains the specified element.
      Specified by:
      contains in interface IntCollection
      Overrides:
      contains in class AbstractIntCollection
      See Also:
      Collection.contains(Object)

    • clear

      public void clear()

      To increase object reuse, this method does not change the table size. If you want to reduce the table size, you must use trim(long).

      Specified by:
      clear in interface java.util.Collection<java.lang.Integer>
      Specified by:
      clear in interface java.util.Set<java.lang.Integer>
      Overrides:
      clear in class java.util.AbstractCollection<java.lang.Integer>

    • iterator

      public IntIterator iterator()
      Description copied from interface: IntCollection
      Returns a type-specific iterator on the elements of this collection.
      Specified by:
      iterator in interface java.util.Collection<java.lang.Integer>
      Specified by:
      iterator in interface IntCollection
      Specified by:
      iterator in interface IntIterable
      Specified by:
      iterator in interface IntSet
      Specified by:
      iterator in interface java.lang.Iterable<java.lang.Integer>
      Specified by:
      iterator in interface java.util.Set<java.lang.Integer>
      Specified by:
      iterator in class AbstractIntSet
      Returns:
      a type-specific iterator on the elements of this collection.
      See Also:
      Iterable.iterator()

    • spliterator

      public IntSpliterator spliterator()
      Description copied from interface: IntSet
      Returns a type-specific spliterator on the elements of this set.

      Set spliterators must report at least Spliterator.DISTINCT.

      See Set.spliterator() for more documentation on the requirements of the returned spliterator.

      Specified by:
      spliterator in interface java.util.Collection<java.lang.Integer>
      Specified by:
      spliterator in interface IntCollection
      Specified by:
      spliterator in interface IntIterable
      Specified by:
      spliterator in interface IntSet
      Specified by:
      spliterator in interface java.lang.Iterable<java.lang.Integer>
      Specified by:
      spliterator in interface java.util.Set<java.lang.Integer>
      Returns:
      a type-specific spliterator on the elements of this collection.

    • forEach

      public void forEach​(java.util.function.IntConsumer action)
      Description copied from interface: IntIterable
      Performs the given action for each element of this type-specific Iterable until all elements have been processed or the action throws an exception.
      Specified by:
      forEach in interface IntIterable
      Parameters:
      action - the action to be performed for each element.
      See Also:
      Iterable.forEach(java.util.function.Consumer)

    • trim

      public boolean trim()
      Rehashes this set, making the table as small as possible.

      This method rehashes the table to the smallest size satisfying the load factor. It can be used when the set will not be changed anymore, so to optimize access speed and size.

      If the table size is already the minimum possible, this method does nothing.

      Returns:
      true if there was enough memory to trim the set.
      See Also:
      trim(long)

    • trim

      public boolean trim​(long n)
      Rehashes this set if the table is too large.

      Let N be the smallest table size that can hold max(n,size64()) entries, still satisfying the load factor. If the current table size is smaller than or equal to N, this method does nothing. Otherwise, it rehashes this set in a table of size N.

      This method is useful when reusing sets. Clearing a set leaves the table size untouched. If you are reusing a set many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient sets.

      Parameters:
      n - the threshold for the trimming.
      Returns:
      true if there was enough memory to trim the set.
      See Also:
      trim()

    • size

      @Deprecated public int size()
      Deprecated.
      Description copied from interface: Size64
      Returns the size of this data structure, minimized with Integer.MAX_VALUE.

      This default implementation follows the definition above, which is compatible with Collection.size().

      Specified by:
      size in interface java.util.Collection<java.lang.Integer>
      Specified by:
      size in interface java.util.Set<java.lang.Integer>
      Specified by:
      size in interface Size64
      Specified by:
      size in class java.util.AbstractCollection<java.lang.Integer>
      Returns:
      the size of this data structure, minimized with Integer.MAX_VALUE.
      See Also:
      Collection.size()

    • size64

      public long size64()
      Description copied from interface: Size64
      Returns the size of this data structure as a long.
      Specified by:
      size64 in interface Size64
      Returns:
      the size of this data structure.

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface java.util.Collection<java.lang.Integer>
      Specified by:
      isEmpty in interface java.util.Set<java.lang.Integer>
      Overrides:
      isEmpty in class java.util.AbstractCollection<java.lang.Integer>

    • clone

      public IntOpenHashBigSet clone()
      Returns a deep copy of this big set.

      This method performs a deep copy of this big hash set; the data stored in the set, however, is not cloned. Note that this makes a difference only for object keys.

      Returns:
      a deep copy of this big set.

    • hashCode

      public int hashCode()
      Returns a hash code for this set. This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.
      Specified by:
      hashCode in interface java.util.Collection<java.lang.Integer>
      Specified by:
      hashCode in interface java.util.Set<java.lang.Integer>
      Overrides:
      hashCode in class AbstractIntSet
      Returns:
      a hash code for this set.